橄榄油微乳体系的相行为及影响因素研究

本文以大豆卵磷脂和司盘80(Span80)复配为表面活性剂,乙醇为助表面活性剂,构建橄榄油微乳体系。采用拟三元相图法,考察亲水亲油平衡值(HLB值)、表面活性剂与助表面活性剂的比值(Km值)、盐浓度等因素对微乳体系相行为的影响,并通过电导率、负染透射电镜等方法研究微乳体系的结构,以优化体系配方、考察微乳液的形成规律。结果表明:大豆卵磷脂与Span80以质量比为3:1复配为混合表面活性剂,并与助表面活性剂无水乙醇按质量比(Km值)为2:1混合,所形成的大豆卵磷脂/Span80/乙醇/橄榄油/水微乳区域面积最大;甘油或少量盐离子的加入,可以在一定程度上增大微乳单相区的面积,但当盐浓度(C_NaCl)大于4 mol/L时,微乳区域面积明显减小;在大豆卵磷脂/Span80/橄榄油/乙醇/甘油/水微乳体系中,当水相(w_水/w_甘油=1:1)含量大于22 wt%时,体系逐渐由W/O型转变为双连续型结构。当水相含量超过30 wt%,体系则发生相分离。此研究为橄榄油微乳液的制备及应用提供理论和技术支持。     

胡椒叶精油微乳液的构建及其抗氧化活性分析

本研究的目的是构建一种改善胡椒叶精油在水相环境中应用的微乳体系.以胡椒叶为原料,采用水蒸汽蒸馏法提取胡椒叶精油,通过绘制伪三元相图选择合适的微乳液组分制备胡椒叶精油微乳液,考察不同表面活性剂、助表面活性剂和Km值等因素对微乳区域面积的影响.最终制备以Tween 80为表面活性剂,无水乙醇为助表面活性剂,去离子水为水相的...     

全稀释食品级单辛酸甘油酯微乳体系的构建

以单辛酸甘油酯为油相,通过拟三元相图方法,研究了吐温20、60、80以及单硬脂酸甘油酯、尼泊金乙酯等表面活性剂,乙醇、丙二醇、正丁醇等助表面活性剂对于微乳体系增溶能力的影响.结果表明,添加醇有助于形成微乳体系,油相中醇的比例越高,微乳相越大,但表面活性剂相中醇的含量不易过多;微乳体系的水相全稀释性主要取决于油与表面活性剂的质量比Wo/Ws,在单辛酸甘油酯/吐温80/乙醇/水和单辛酸甘油酯/吐温80/丙二醇/水体系中,当Wo/Ws＞1时,即使添加足量的醇也无法形成全稀释微乳.而且,表面活性剂的复配不一定具有增效作用.最后,确定微乳配方为油相:单辛酸甘油酯与丙二醇质量比2∶1;表面活性剂相:吐温80与乙醇质量比为2∶1;水相:双蒸水.该食品级单辛酸甘油酯微乳单相区面积为73.81％,具有3条可无限稀释通道.盐离子浓度和pH的稳定性研究表明,该微乳体系在NaCl浓度0.1～0.6mol/L范围内稳定性较好,且受pH影响较小.     

微乳的稳定性研究

本实验以单辛酸甘油酯,丙二醇质量比2∶1为油相;吐温80,乙醇质量比2∶1为表面活性剂相,双蒸水为水相制备出具有3条无限稀释通道的食品级微乳,通过粒径分析,浑浊度测定,Zeta电位比较,离心及稳定性实验,研究稀释,盐离子浓度,酸碱性,温度对单辛酸甘油酯微乳稳定性的影响。实验制备的T82-100微乳,在NaCl浓度0.1~0.6mol/L,pH3~8,温度0~40℃之间,吸光值0.015,采用食品级原料制备的单辛酸甘油酯抑菌性T82微乳不仅稀释稳定性强,且具有较好的耐盐离子、pH及温度特性,整个实验中均保持均一透明的稳定状态。结果表明示选择合适的表面活性剂、助表面活性剂及恰当的比例,能制备出全稀释的稳定微乳,这对扩大微乳在食品中的应用提供可能。     

香茅草精油微乳液的构建及其抗氧化活性分析

本研究的目的是构建一种改善香茅草精油在水相环境中应用的微乳体系。以香茅草为原料,采用水蒸汽蒸馏法提取香茅草精油以及GC-MS联用技术对精油成分进行定性分析。通过绘制伪三元相图选择合适的微乳液组分制备香茅草精油微乳液,考察不同表面活性剂、助表面活性剂、Km值、pH值和离子强度等因素对微乳区域面积的影响。最终制备以Tween80为表面活性剂,无水乙醇为助表面活性剂,去离子水为水相的O/W型香茅草精油微乳液。其理化性质为:pH为6.73±0.02、黏度为15.50±0.11 mPa/s、电导率为108.90±0.21μs/cm、平均粒径为16.50±0.53 nm。最后,通过用DPPH,ORAC和PSC方法测定及比较香茅草精油与香茅草精油微乳液的抗氧化活性。结果表明,香茅草精油微乳液在水相环境中的抗氧化活性显著优于香茅草精油的效果(p0.05)。     

微乳液皮革脱脂剂的制备及性能研究

研究了微乳液主表面活性剂种类及配比、助表面活性剂种类、主表面活性剂与助表面活性剂比值及主表面活性剂与D-柠檬烯的比值对伪三相图面积的影响,通过盐度扫描优化了水相中Na Cl的用量,获得了微乳液最优制备工艺;通过动态光散射、电导率等对微乳液结构性能进行了表征。结果表明：当脂肪醇聚氧乙烯醚、十二烷基硫酸钠、异构醇醚为主表面活性剂且三者质量比为1∶1∶1,正丁醇为助表面活性剂,主表面活性剂与助表面活性剂的比值为2∶1,主表面活性剂与D-柠檬烯的质量比为2∶1,Na Cl用量为4.8%水溶液为水相时,得到的双连续微乳液微乳区面积最大;微乳液的粒径为51.8 nm,多分散指数为0.274,具有较小的粒径及较好的分散性,表面张力为27.3 m N/m,界面张力为0.09 m N/m,乳化、润湿和稳定性能优异;微乳液皮革脱脂剂对多脂绵羊酸皮的脱脂率高于市售皮革脱脂剂。     

板栗花精油微乳的制备工艺

本文采用转相乳化法制备板栗花精油微乳,并通过伪三元相图考察表面活性剂、助表面活性剂、表面活性剂与助表面活性剂的比值(Km值)和油相对微乳形成的影响,以确定板栗花精油微乳的最优制备工艺参数。结果表明:板栗花精油微乳的最佳工艺为:聚乙二醇硬脂酸酯-15(HS-15)为表面活性剂,甘油为助表面活性剂,Km为2,油酸乙酯(EO)与精油等比例混合为油相,所制备的板栗花精油微乳为O/W型。以最佳微乳配方中混合表面活性剂与油相比例7∶3为试样,微乳的特性参数电导率、黏度和p H分别为180.2μs/cm,44.7 m Pa·s和6.66。此研究为板栗花精油微乳的制备及应用提供技术支持。     

表没食子儿茶素没食子酸酯(EGCG)抗氧化微乳液的制备与表征

以肉豆蔻酸异丙酯为油相,吐温80-司盘80复配表面活性剂(HLB为6)为表面活性剂,乙醇为助表面活性剂(Km值为4∶1)制备了油包水型的表没食子儿茶素没食子酸酯(EGCG)抗氧化微乳液,并对其稳定性和抗氧化活性进行考察。通过测定电导率鉴别微乳液类型,纳米粒度仪测定微乳液的粒径,考察25℃条件下贮藏时间对微乳粒径的影响,评价微乳液的稳定性。同时,采用氧化稳定仪测定EGCG微乳液在花生油和亚麻籽油中的抗氧化活性。结果表明,微乳液外观澄清透明,在25℃贮藏条件下的稳定性好,放置50 d后微乳液的粒径变化小,放置期间未出现分层、破乳现象,并且在植物油中表现出较好的抗氧化活性。     

食品级肉豆蔻酸异丙酯微乳的制备研究

本文以肉豆蔻酸异丙酯为原料,筛选出肉豆蔻酸异丙酯空白微乳的最佳配方。首先采用伪三元相图法,以微乳区面积为指标,筛选出表面活性剂和助表面活性剂;探究表面活性剂与助表面活性剂质量之比Km值与亲水亲油平衡值(HLB值)对微乳形成的影响,然后以离心和染色实验来判断微乳的稳定性和构型。结果表明:当以肉豆蔻酸异丙酯作为油相,吐温80复配司盘80作为复合表面活性剂,无水乙醇为助表面活性剂(表面活性剂∶助表面活性剂∶IPM=4∶2∶4),且Km=2∶1,HLB=7.5时,形成的微乳液稳定性最好。此条件下,油包水型微乳的最大载水量为15.3%。因此可以说明伪三元相图法制备肉豆蔻酸异丙酯方法方便可行。     

丁香油微乳的制备及抑菌活性研究

为了改善丁香油水相溶解性及储藏稳定性差的应用缺陷,以可稀释微乳包载丁香油。通过比较丁香油微乳拟三元相图中微乳区面积(S_(ME))和最小可稀释比(DR),选择聚氧乙烯蓖麻油(Cremophor)EL 30与无水乙醇以21(质量比)为混合表面活性剂,水相环境为中性制备丁香油微乳。进一步采用电导率法和流变法对微乳构型进行鉴定,并选择O/W中心区域微乳:混合表面活性剂/丁香油/水(质量比)=16/4/80,Km=2,进行抑菌活性评价。结果表明,微乳包埋体系并未改变丁香油的抑菌活性。同时,通过检测丁香油微乳在稀释和储藏过程中的粒径变化,发现此微乳能保持良好的稀释和储藏稳定性。因此,该微乳在有效改善丁香油的水溶性和储藏稳定性的同时,对其抑菌活性没有影响。     

Preparation Methods for Monodispersed Garlic Oil Microspheres in Water Using the Microemulsion Technique and Their Potential as Antimicrobials

Garlic oil is considered as a natural broad‐spectrum antibiotic because of its well‐known antimicrobial activity. However, the characteristics of easy volatility and poor aqueous solubility limit the application of garlic oil in industry. The purpose of the present work is to develop and evaluate an oil‐free microemulsion by loading garlic oil in microemulsion system. Microemulsions were prepared with ethoxylated hydrogenated castor (Cremophor RH40) as surfactant, n‐butanol (or ethanol) as cosurfactant, oleic acid‐containing garlic oil as oil phase, and ultrapure water as water phase. The effects of the ratio of surfactant to cosurfactant and different oil concentration on the area of oil‐in‐water (O/W) microemulsion region in pseudoternary phase diagrams were investigated. The particle size and garlic oil encapsulation efficiency of the formed microemulsions with different formulations were also investigated. In addition, the antimicrobial activity in vitro against Escherichia coli and Staphylococcus aureus was assessed. The experimental results show that a stable microemulsion region can be obtained when the mass ratio of surfactant to cosurfactant is, respectively, 1:1, 2:1, and 3:1. Especially, when the mixture surfactants of RH40/n‐butanol 2/1 (w/w) is used in the microemulsion formulation, the area of O/W microemulsion region is 0.089 with the particle size 13.29 to 13.85 nm and garlic oil encapsulation efficiency 99.5%. The prepared microemulsion solution exhibits remarkable antibacterial activity against S. aureus.     

食品级刺五加叶黄酮微乳的制备及功能特性

黄酮类物质的溶解度低,耐碱性和抗光解能力差,化学性质很不稳定,限制了其在食品中的应用,而微乳是一种良好的载体,可解决黄酮难以利用的问题。本研究应用滴定法绘制伪三元相图来考察不同的表面活性剂、助表面活性剂、表面活性剂与助表面活性剂的质量比（Km）、油相等对微乳形成的影响,从中筛选出最佳微乳制备配方。利用透射电子显微镜和粒径分析仪研究微乳粒子的形态和粒径分布。同时以刺五加叶为原料,采用微乳化技术制备刺五加叶黄酮微乳,以超氧阴离子自由基、羟自由基及1,1-二苯基-2-三硝基苯肼自由基的清除率来考察黄酮微乳的抗氧化能力,以抑菌圈实验研究黄酮微乳的抑菌性能,以刺五加叶黄酮为对照。结果发现,以肉豆蔻酸异丙酯为油相、Tween-80为表面活性剂、无水乙醇为助表面活性剂,且Km＝2时得到的微乳区域面积最大,微乳平均粒径约18.3 nm,高速离心和长时间放置后体系均匀透明、未见分层、稳定性好。抗氧化实验表明,刺五加叶黄酮微乳的抗氧化能力优于刺五加叶黄酮对照。在抑菌圈实验中,黄酮微乳对大肠杆菌、金黄色葡萄球菌、沙门氏菌及荧光假单胞菌的抑菌效果均好于刺五加叶黄酮对照。     

Formulation of a cosurfactant-free O/W microemulsion using nonionic surfactant mixtures

ABSTRACT:  A cosurfactant-free O/W microemulsion composed of oil, a mixture of hydrophilic and hydrophobic surfactants, and water has been developed using food-grade components as a nutrient delivery system. We started our investigation to monitor the phase behavior of this system based on a hydrophilic surfactant (Tween 80). From a phase diagram, the weight ratio of 5.4:33.8:60.8 = oil:surfactant:water was selected as a combination ratio for the O/W microemulsion system. We also investigated the combination effect of different hydrophobic surfactants to Tween 80 on microemulsion formation. Use of hydrophobic surfactants with Tween 80 produced smaller droplets than Tween 80 alone. Rheological studies showed that all microemulsions followed shear-thinning behavior. The turbidity of microemulsions did not change after accelerated stability tests, indicating that this microemulsion system was stable under the given harsh conditions. When docosahexaenoic acid (DHA) oil was applied to this microemulsion system, the particle size and the turbidity were not significantly changed. Dilution with a different aqueous medium, either water or acidic fluid, did not significantly change the microemulsion turbidity. DHA oil incorporated in microemulsion showed higher oxidation stability than free DHA oil.     

In vitro and in vivo antifungal activity of a water-dilutable cassia oil microemulsion against Geotrichum citri-aurantii

BACKGROUND: Recently, food‐grade microemulsions have been of increasing interest to researchers and have shown great potential in industrial applications. In this study a food‐grade water‐dilutable microemulsion system with cassia oil as oil, ethanol as cosurfactant, Tween 20 as surfactant and water was developed and its antifungal activity in vitro and in vivo against Geotrichum citri‐aurantii was assessed. RESULTS: The phase diagram results confirmed the feasibility of forming a water‐dilutable microemulsion based on cassia oil. One microemulsion formulation, cassia oil/ethanol/Tween 20 = 1:3:6 (w/w/w), was selected with the capability to undergo full dilution with water. The average particle size was 6.3 nm. The in vitro antifungal experiments showed that the microemulsion inhibited fungal growth on solid medium and prevented arthroconidium germination in liquid medium and that cassia oil had stronger activity when encapsulated in the microemulsion. The in vivo antifungal experiments indicated that the water‐dilutable microemulsion was effective in preventing postharvest diseases of citrus fruits caused by G. citri‐aurantii. CONCLUSION: The results of this study suggest a promising utilisation of water‐dilutable microemulsions based on essential oils for the control of postharvest diseases. Copyright © 2012 Society of Chemical Industry     

Stability and characterisation of phospholipid-based curcumin-encapsulated microemulsions

The ternary phase diagram of a curcumin-encapsulated O/W microemulsion system using food-acceptable components, lecithin and Tween 80 as the surfactants and ethyl oleate as the oil phase, was constructed. The stability and characterisation of curcumin in microemulsion were investigated. The results indicated that a composition of curcumin microemulsion (DI water: surfactants (the mole ratio of lecithin/Tween 80 was 0.3): EO = 10:1.7:0.4 in wt ratio) was stable for 2 months with an average diameter of 71.8 ± 2.45 nm, as detected by UV–Vis spectra and diameter distributions. The microemulsion possesses an ability to be diluted with aqueous buffer without destroying its structure for 48 h. A skin permeation study for testing the penetration effect of various curcumin loading in the microemulsions with different particle diameters was also performed and discussed in this contribution.     

Solubilisation of soybean oil in microemulsions using various surfactants

Microemulsions are transparent, isotropic solutions of oil, water and surfactant (and possibly cosurfactant) which are thermodynamically stable, and have been much studied in terms of pharmaceutical and cosmetic applications. However, the application of microemulsions in foods has been limited both due to toxic or irritant nature of ionic surfactants and the difficulty of solubilising large triglycerides. Three surfactants, food-grade ethoxylated mono- and diglycerides (EMD) and phospholipids, and non-food-grade polyoxyethylene oleyl ether (POE) were examined for their ability to form microemulsions using soybean oil, and their areas of formation expressed on phase diagrams. Microemulsions prepared with EMD and phospholipids required the presence of a short-chain alcohol for formation. Both oil/water (o/w) and water/oil (w/o) microemulsions could be formed using EMD, and the microemulsion area of the phase diagram increased on addition of sucrose and increase in temperature. Depending on sucrose and ethanol concentrations, microemulsions formed with EMD were found to retain their integrity at temperatures below which they formed. Microemulsions could be formed using phospholipids, but only at high surfactant concentration and in the presence of a short-chain alcohol. O/w microemulsions containing 10% oil (w/w) were prepared with POE at surfactant concentrations of >20% (w/w). Dynamic light scattering of microemulsion samples diluted with water indicated particle radii of 6.5 nm. Freeze-fracture SEM showed the structures to be of a droplet type, however, this was more evident at higher surfactant/oil concentrations. The results indicated that it is possible to formulate microemulsions at low EMD and POE surfactant concentration. These microemulsions systems may potentially be used for encapsulation of oil-soluble bioactives, e.g. α-tocopherol, in food systems.     

响应面法优化茴香精油提取工艺及其微乳特性和货架期研究

本研究通过响应面法对茴香精油提取工艺进行优化,然后以茴香精油为油相、Tween 80+40为表面活性剂、丙三醇为助表面活性剂制备茴香精油微乳液体系,利用流变法、粒度仪及还原反应,对茴香精油微乳构型、粒径、总还原力及贮藏性进行探究。结果表明,当料液比1:8.40 g/mL,浸提时间4.09 h,颗粒粒度80目,浸提温度80 ℃时,茴香精油得率高达15.99%±0.10%。制备的茴香精油微乳粒径为30.92±0.13 nm,当水分含量高于60%时,为稳定的O/W型微乳。茴香精油的乳化明显提升了茴香精油的总还原力。根据化学反应动力学原理,建立Arrhenius方程为:k=2518.85·e?35583.09/RT,该模型预测茴香精油微乳在20、35、50和65 ℃下能贮藏 1899.18、932.03、492.94和 271.51 h,最大相对误差8.73%,误差较小,可准确预测该微乳的货架期。     

Microemulsions: a potential delivery system for bioactives in food

Microemulsions are thermodynamically stable, transparent, low viscosity, and isotropic dispersions consisting of oil and water stabilized by an interfacial film of surfactant molecules, typically in conjunction with a cosurfactant. Microemulsions (so-called due to their small particle size; 5-100 nm) have found application in a wide variety of systems, such as pharmaceutical and oil recovery, but their application in food systems has been hindered by the types of surfactant permissible for use in food. The objective of this review is to provide an overview of the structures and phase behavior of microemulsions, methods of microemulsion formation, and techniques which may be used for characterization. A comprehensive review of previous work on both food-grade microemulsion systems, and non-food-grade systems of specific food interest is included. The application of microemulsions as reaction media, their ability to solubilize proteins and hence their use as a separation technique is also documented. In addition, attention is focused on the application of microemulsions as delivery systems for delivery of bioactive compounds, and the links between microemulsions and increased bioavailability. Future research, both applied and fundamental, should focus on surfactants which are not restricted for use in foods.     

Lemon oil solubilization in mixed surfactant solutions: Rationalizing microemulsion & nanoemulsion formation

Lipophilic functional ingredients are usually incorporated into aqueous-based foods and beverages in the form of colloidal dispersions. In this study, we investigated the rate and extent of solubilization of emulsified lemon oil in mixed non-ionic surfactant solutions (buffer: propylene glycol = 2:1): sucrose monopalmitate (SMP) and/or Tween 80 (T80). The influence of surfactant concentration, type, and mixing ratio on lemon oil solubilization was investigated, with the aim of identifying suitable conditions for preparing stable microemulsions and nanoemulsions. Solubilization was monitored by measuring changes in light scattering by lemon oil droplets after they were dispersed in surfactant solutions (pH 7). The solubilization process was rapid (<few minutes), with the rate increasing with increasing surfactant concentration. For a particular surfactant type and concentration, lemon oil was transferred from nanoemulsion droplets into microemulsion droplets until a critical lemon oil concentration (C_sat) was reached, after which it remained as nanoemulsion droplets. The value of C_sat increased with increasing surfactant concentration and was higher for SMP than Tween 80. The impact of storage at pH 3.5 on the physical stability of microemulsions and nanoemulsions was examined. Acid stable colloidal dispersions could not be formed using SMP alone. However, relatively stable nanoemulsions and microemulsions could be formed when ≥75 or 50 wt% Tween 80 was incorporated into the surfactant phase, respectively. This study provides important information for the rational design of food-grade colloidal delivery systems for encapsulating and delivering functional lipids for food and beverage applications.